Big port head flow tuning
04-23-2009, 06:23 PM
Post: #11
Big port head flow tuning
Diskovod Wrote:Yeah, man! Thanks for points! Hurray!

I'm thinking about removing these boundaries also as there are no ones on Formula Atlantic heads...

and then slice some mms from the bottom of the head to have 11:1 compression...

When those areas you marked are removed, the term is commonly called "de-shrouding". When removed it is easier to run addition compression, because these high spots get hot, and can cause pre-ignition. The negatives is removing enough, and yet not "hogging" the chamber out... each particle you remove from the chamber DECREASES your compression! It is advised to get the chambers measured accurately *IF* you decide to mess inside the combustion chambers, that way you can make each chamber the same volume, therfore providing equal performance

As a comparison to your Atlantic head, here is my street prepared head....

[Image: AEU86 AE86 - Big port head flow tuning][Image: AEU86 AE86 - Big port head flow tuning]


I did my chamber work based on the TRD N2 engines (a bit closer to your street performance type)
[Image: AEU86 AE86 - Big port head flow tuning]



Oh... you'll need one of these to measure chambers...
[Image: AEU86 AE86 - Big port head flow tuning]

Dan -

You can |Sad .... OR you can ask for help!!!

OST Porting service - http://hachiroku.net/forums/showthread.php?t=19991
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04-29-2009, 01:01 AM
Post: #12
Big port head flow tuning
oldeskewltoy Wrote:
Diskovod Wrote:Yeah, man! Thanks for points! Hurray!

I'm thinking about removing these boundaries also as there are no ones on Formula Atlantic heads...

and then slice some mms from the bottom of the head to have 11:1 compression...

When those areas you marked are removed, the term is commonly called "de-shrouding". When removed it is easier to run addition compression, because these high spots get hot, and can cause pre-ignition. The negatives is removing enough, and yet not "hogging" the chamber out... each particle you remove from the chamber DECREASES your compression! It is advised to get the chambers measured accurately *IF* you decide to mess inside the combustion chambers, that way you can make each chamber the same volume, therfore providing equal performance

As a comparison to your Atlantic head, here is my street prepared head....

[Image: AEU86 AE86 - Big port head flow tuning][Image: AEU86 AE86 - Big port head flow tuning]


I did my chamber work based on the TRD N2 engines (a bit closer to your street performance type)
[Image: AEU86 AE86 - Big port head flow tuning]



Oh... you'll need one of these to measure chambers...
[Image: AEU86 AE86 - Big port head flow tuning]

Respect!

Sure, man!

"each particle you remove from the chamber DECREASES your compression!"
Yep, I know that, I'm gonna shave the head anyway.

Yeah, I'll need to measure them... that's not hard, but it take a little time to make that fluid based measuring stuff Tongue

Also I suddenly found through Club4AG your files on the Box with TRD N2 manuals! Thanks for sharing! Hurray!

I'm going to pull out my engine soon, will be showing pics of progress and be likely to get some more advices. Anyway thanks for your posts! Thumbs up!

P.S. Do you know what was the compression ratio for Formula Atlantic?

1972 Ford Taunus (drift project)
1984 Toyota Celica AA63 (4AGE, 5MT, IRS)
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05-04-2009, 07:03 PM
Post: #13
Big port head flow tuning
Diskovod Wrote:P.S. Do you know what was the compression ratio for Formula Atlantic?


http://www.geocities.com/motorcity/7177/...specs.html - not sure how accurate....

Dan -

You can |Sad .... OR you can ask for help!!!

OST Porting service - http://hachiroku.net/forums/showthread.php?t=19991
Find all posts by this user


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